A year later, I saw the movie at a rental store. I had totally forgotten the name of the Stephen King story and rented it only because I knew it had been nominated for the Oscars.
30 minutes in, I said "This seems familiar!" And then "Oh, I bet this will be a great movie." It was.
I think it's worthy of being amongst the top. It has elements that appeal to a broad audience (not boxed into a specific genre). Great story. Great narration. Great cinematography and sound.
The only other movies in the Top 10 that I think could be ranked higher are The Godfather (which for many years was the top ranked), and The Good, The Bad and The Ugly. For both of these movies, I know a lot more people who didn't like them. I only know one person who didn't like The Shawshank Redemption.
Apt Pupil was also made into a movie but didn't do as well.
Here we go...
The SHORT BUT STILL LONG version.
Shawshank was a flop. Made no money in theaters. This made its home video and, most importantly, broadcasting rights SUPER CHEAP.
TBS and TNT were two basic cable channels that bought the rights to show it. And they showed it. CONSTANTLY. This is an era before streaming. If you wanted to watch a movie at home you either bought it, rented it, or caught it on cable. Since those two networks basically aired the movie on a damn near continuous loop for YEARS, everybody saw it.
Now it was super common to find movies by flipping through them on cable. But Shawshank benefited from its almost episodic story structure. Go back and watch the movie. It's not very complicated and there are multiple digressions. Like the Brooks bit, for example, where for like 5 to 10 minutes it's like a short film. The end of the film with the prison break is like that too.
Just a bunch of really good, very satisfying sequences that don't reaaaaally ask much of you if you come across it without seeing what came before it. It's not a complicated heist film. In fact, anecdotally, it took me YEARS to see the beginning of this film even after I had watched it like a dozen times. The first time I watched it all the way through I was like "oh shit. There was a trial?"
This made the movie VERY EASY to drop in on as you were flipping. "Oh it's this part!" you would say. Or you knew the part you liked was coming up.
So this was all happening in the late 90s. And the movie just slowly, stealthily became everybody's favorite movie. So when people started wandering onto the internet in that time before time and found themselves on IMDB, Shawshank got all the votes from those Gen Xers and Millenials who had seen the movie 50 times in bits and pieces on cable.
And it all happened before you started really getting concerted efforts to vote "against" things like it was some crazy competition.
EDIT: I think some very angry people are confusing what I wrote above with not believing the movie to be any good. The movie is exceptional which made all of the rest of it possible. But exceptional films fall into obscurity all the time and there has to be some other force at work outside of its intrinsic "goodness" to get eyeballs back on the screen. Accessibility to your audience is absolutely a factor.